<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="../vue.min.js"></script>
    <title>Document</title>
</head>
<body>
    <divid="app">
        <p>First name: <input type="text" v-model="firstName"></p>
        <p>Last name: <input type="text" v-model="lastName"></p>
        <p>fullname:{{fullname}}</p>
        <button @click="change">改变fullname</button>
    </div>
</body>
<script>
    var vm = new Vue({ 
    el: '#app',
    data: {
        firstName: '',
        lastName:''
    },
        methods: { 
            change() {
                this.fullname ='Harry Potter';
            }
        },
        computed:{
            fullname: {
                get: function() {
                    return this.firstName + ''+ this.lastName;
                },
                set: function(newVal) {
                    var arr = newVal.split(' ');
                    this.firstName = arr[0];
                    this.lastName = arr[l];
                }
            }
        }
    })
</script>
</html>